| MiRNA is a kind of single-stranded RNA molecules with the length from 20 to 25 nucleotides in eukaryotic cell. It shows evolutionary sequence conservation. Up to data, miRNAs have been reported in nearly 1000 species. It plays various roles in life activities, including organ formation, development, viral defence, hematopoiesis, cell proliferation and apoptosis, fat metabolism and so on. MiRNA is produced by a series of shear processing nuclease from longer primary transcripts into small molecules of non-coding RNA. It functions in means of complementary base pairing with targetable mRNA, and the degree of complementarity guides either the silencing complex or just repression of targetable mRNA.Though studing in miRNA has been always as a hot spot in biological research recently, how it functions in the biological process is still an open question. This paper has studied on miRNAs and their precursors, and some of the important sites were analyzed by exploring bio-statistical method to prove the importance of the conservatism in miRNAs' formation and lies a hypothesis on the primary structure of the precursor.In this study, animals, plants and viruses were divided into three categories, and each category was even subdivided into four groups, by calculating the single base of information redundancy (D1 (L)) and the adjacent base information redundancy (D2 (L) ). Information entropy analysis has been reported on miRNA and their precursors, and some of the important sites of the primary structure of miRNA precursors were studied, and based on the perspective, the interpretation of information entropy was elaborated for the miRNA formations.The results showed that the adjacent base information redundancy of information contains more information than a single base, despite the various groups in the (D1 (L) and D2 (L) value was positively correlated with changes in the basic trend. These important positions in animal is less conservative than that in plants. The sequence conservatism in some positions shows that some positions are important in the Dicer enzyme process, identifying and cutting the precursors, especially in animals. |
